The solutions for the practice ideas:
[(model, color, size) for model in models for color in colors for size in sizes]
princesses_from_frozen = [frozen_char for frozen_char in frozen for princess in princesses for i_like in princesses_i_like if frozen_char == princess and frozen_char == i_like]
[F"{name} {surname} - {age}" for name, surname, age in zip(names, surnames, ages) if int(age) > 20]